The present invention relates to T-tubes for utilization in surgical procedures and the like and, in particular, to a flexible T-tube for implantation in human body ducts, such as the common bile duct, to provide drainage or access following surgical procedures.
T-tubes have been utilized in surgical and other medical procedures for many years. The conventional T-tube has a crossbar with an internal fluid flow directing lumen or channel which is typically positioned in a duct and a stem also with an internal lumen which communicates with the lumen of the crossbar and which is positioned to pass through the duct to drain to a location remote from the duct.
Certain modifications in T-tubes have been developed to produce advantageous effects. For example, Goldberg et al. in their U.S. Pat. No. 3,835,863 disclose a T-tube having slots along the side of the crossbar opposite the juncture thereof with the stem, such that opposite sides of the crossbar intermesh together to form a smaller cross-section and, therefore, less trauma upon withdrawl of the T-tube from the patient. In their U.S. Pat. No. 4,142,528 Whelan et al. disclosed another common modification which often occurs during surgery wherein the surgeon removes a substantial portion of the back wall of the crossbar.
A common use for a flexible T-tube is for drainage of the common bile duct following surgery performed on the gallbladder and/or common bile duct. In particular, the gallbladder is a lined pouch which is connected to the common bile duct by the cystic duct intermediate the liver and duodenum. Normally, bile flows down the common bile duct into the duodenum to assist in the digestion of fatty foods.
Between meals, bile may be stored in the gallbladder. Gallstones which produce both pain and other symptoms may form in the gallbladder and hamper flow of bile in the tract between the gallbladder and the duodenum or between the liver and duodenum. This often requires surgical procedures to remove the gallstones and may also require removal of the gallbladder.
Normally, an incision is made in the common bile duct between the cystic duct and the duodenum in which a T-tube is inserted following the surgery. The incision in the common bile duct is sewn together on opposite sides of the stem of the T-tube so that only the stem protrudes therefrom. The stem is passed through the abdominal wall of the patient and the T-tube is left in place normally in the range of from 7 to 21 days following surgery. During this period of time, the T-tube allows excess bile to drain from the common bile duct. Normally, after approximately this amount of time, the liver modifies its production of bile to adjust for the gallbladder no longer being present to provide storage. Sometimes the T-tube is utilized to also flush the common bile duct or for other purposes while still inserted therein. After serving its useful purpose, the T-tube is pulled by the distal end of the stem such that opposite sides of the crossbar collapse together and it is then pulled from the body in this manner.
Unfortunately, trauma occurs at the opening for the stem through the common bile duct as the crossbar is pulled through. Attempts have been made to reduce this trauma through various modifications to the T-tube, such as are shown in the above mentioned Goldberg et al. patent. Applicant has found that the trauma can be reduced by making the cross-section of the stem, where is passes through the wall of the common bile duct, elliptical in shape, especially where the largest or major axis of the elliptical cross-section is aligned parallel to the longitudinal axis of the lumen of the common bile duct. This elliptical cross-section produces numerous advantages.
In particular, as compared to circular stems, the elliptical cross-section allows reduction in the width of the stem along the minor axis of the elliptical cross-section as the major axis is widened while still allowing for passage of approximately the same volume through a central lumen thereof. Alternatively, the width of the lumen along the minor axis may be the same as the diameter of a circular stem, yet the internal flow capacity or working space can be increased as the major axis is lengthened.
As wounds or incisions along the common bile duct heal from side to side rather than from the end to the middle, a wound left after removal of an elliptical tube, although relatively longer, has a healing time which is less than the healing time associated with removal of a circular stem capable of containing the same flow and there is less chance of excessive scar formation which could lead to stricture or narrowing of the common bile duct after healing.
Secondly, during suturing of the incision following implantation of the T-tube, it is necessary to suture tightly around the stem to form a liquid seal. For a T-tube suitable for handling a given flow volume, the round tubes produce greater stretching of tissue about the stem than do elliptical tubes as described for the present invention. The greater tension makes suturing more difficult around the circular tubes than around the elliptical tubes as described herein.
Thirdly, under certain circumstances, gallstones may be retained within the common bile duct following surgery. There are techniques for removing these stones without subsequent invasive surgery by introduction of instrumentation through the T-tube. A T-tube of the present invention having a minor axis width equal to that of a circular T-tube leaves a wound after removal which heals approximately as fast as the circular T-tube (as discussed above), but presents a much larger internal working circumference within the tube for insertion of tools making such procedures surgically easier and less traumatic to the surrounding tissue.
Finally, when the T-tube is removed, there is always an associated trauma. Again, in comparing an elliptical T-tube according to the present invention having a minor axis with approximately equal width to a conventional circular T-tube, upon removal, the elliptical tube presents a larger cross-sectional area for passage of the crossbar therethrough as compared with the circular T-tube, yet healing time of the wounds will be approximatley the same.
T-tubes, especially T-tubes for utilization in the common bile duct, are available in many different sizes as the common bile duct normally varies from 0.5 to 1.0 centimeters and, in certain conditions, dilates to 2.5 centimeters or more. Normally, a surgeon selects the outer diameter of the T-tube to generally match the inner diameter of the common bile duct. This means that many different tubular sizes must be available to the surgeon. In addition, in accordance with common procedure, the surgeon will often remove the back side of the T-tube, that is, the side opposite from the side of the tube which abuts against the stitches. Removal of the back side of the tube can be seen in such references as the above discussed Whelan et al. patent. Removal of the back side of the tube could be utilized to adjust the tube to various duct sizes, except that the remaining portion of the tube will retain substantially the same radius as the original tube and, therefore, it will never fit properly within a duct having a different radius.
Therefore, applicant has designed a crossbar formed of two generally planar walls joined in a V-shape which can be trimmed by a surgeon at the time of insertion to conform to the walls of a particular duct into which the surgeon is inserting the tube. In this manner, the surgeon not only can modify a single standard tube to fit a particular need, such as the diameter of virtually any common bile duct; but also the edges of the walls may be sized to abut against the sides of the duct so as to form a snug implantation. Thus, provided that the wall panels are of sufficient initial width, one size of T-tube according to the present invention may be modified to fit virtually all common bile ducts or used for other similar medical procedures requiring a T-tube type drain, including procedures on the kidney and/or ureter and in hysterectomies.